Stable Overclock on the DFI NF680i LT

After taking a few different approaches to overclocking this board/CPU combo, I finally arrived at a 8hr PRIME stable overclock... (click to enlarge images)

With tweaked memory for low-latency (4-3-3-8 1T)...

GTL

An interesting fact is that my stable GTL settings are radically different from the recommended values. I initially discovered this by accident... I originally tried a GTL 2/3 value similar to GTL 0/1 out of frustration and thinking (now erroneously) that perhaps the two GTL settings should be similar.

Later, when I was trying to get Vista to boot at 3.8GHz for fun, I tried every GTL value (changing by 10 and then 5 and then 2) to narrow in on GTL values that would just allow Vista to boot at 3.8GHz... this reinforced my earlier findings... at high FSB overclocks, GTL 2/3 for me had to be close to GTL 0/1. While I'm certain this is not the case for others, it definitely worked out for my particular CPU/board combo.

My situation is most certainly an endorsement for having GTL tuning... since without the ability to tweak GTL values significantly like this, I would not have been able to make this overclock stable. Although without another board without GTL tuning (i.e. the EVGA 680i) to evaluate this theory, I will never really know for sure.

Voltages

In some cases, there is a significant difference between what is set in BIOS and the actual voltage.

Here are my voltage settings, and the actual values reported by BIOS:

CPU VID: 1.6V / 1.53V

DRAM Voltage: 2.34V / 2.30V

NB Core Voltage: 1.74V / 1.6V

SB Core Voltage: 1.62V / 1.58V

HT Link Voltage: 1.60V / 1.58V

The NB is particularly bad as it is off about 0.12V at most settings.

Note that water cooling is essential for running these kinds of voltages on a quad-core.

BIOS Settings

Disabled full-screen logo to better see POST information...

No change...

No change...

Disabled IDE as I have a SATA optical drive...

Not using RAID...

Disabled all other devices...

Set to S3(STR)...

No change...

Set temperature threshold to maximum value as I was tripping the thermal shutdown at default settings...

See my comments on voltages above...

Run linked/synced for best memory performance...

No change... it's apparently important to leave these settings as is for overclocking...

Memory timings (I'll have a new blog post on memory overclocking soon)...

Not using the SI RAID controller so disabled it...

Posted by VirtualRain on Wednesday, May 16, 2007 at 10:19 AM |Permalink

I,m glad to find this, because i just bought same mb and i have not oc this kind of motherboard at all, only intel ar amd but not sli configuration no. 8800GTX-sli will be soon on my rig after my salesman have it.